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Noteworthy observations

Large aspen tortrixSmall, scattered pockets of defoliation caused by the large aspen tortrix
caterpillars occurred along the north shore from Cook County to Duluth
and down into Carlton and Pine Counties. Moths had already emerged
by June 21st .

Forest tent caterpillarForest tent caterpillars can be found throughout northern Minnesota.
In most cases, only scattered clumps of trees have been defoliated but,
in a few cases, areas up to two square miles have heavy defoliation.
Most feeding was finished with caterpillars starting to spin cocoons by
June 21st . The moth flight and egg laying will occur the first part
of July. With the adequate moisture we have been receiving, heavily
defoliated trees should releaf nicely in July.

Birch leaf minerThe first generation was still mining leaves in Duluth as of June 21st
.

Mt. ash sawflyVoracious larvae of the first generation were 1/3 to 5/8 of an
inch long on June 20th in Grand Rapids.

Pale green weevilFirst sightings occurred in mid-June. Although they only feed
on the edge of leaves, they can cause significant damage to berry foliage.

Oak wiltOak wilt disease has become active across much of the southeast. We
are seeing early signs of root graft infections from active centers. Local
news releases have gone out, financial assistance is available for cost
share practices. See section on Community Forest Health Grants.

Oaks recover from anthracnose outbreakThe cool, wet weather that set the environmental stage for an outbreak
of oak anthracnose across much of southeastern Minnesota came to an end
in late May. With improved weather conditions the oaks had time to recover.
New disease free healthy foliage has developed on the trees and they
are on the road to recovery. Recovery shouldn't be a problem this year
given the excellent conditions were now experiencing in this region.